This ledger covers the period May 1902-December 1931. As the account book of final entry, it summarizes transactions relating to the prospecting activities of MECNJ, including its capitalization and its rental of mining properties. Included are stock, cash, patent, and tax accounts; and accounts with Edison, John V. Miller, and investors James Gaunt and Charles M. Schwab. The company was largely inactive after 1903, but transactions were posted to many accounts through 1907. The legal expense account was active through 1920, while Edison's account and the general expense account were active through December 1931. Inserted into the book are two loose pages consisting of draft balance sheets for February 1909 and December 1931. The cover is labeled "Ledger  Mining Exploration Co of N.J.  1-108." The book contains 186 pages and an index; most of the pages are blank.